Ellipsograph



June 6, 1967 M. sAcHs-ENHAUS ETAL 3,323,214

ELLIPSOGRAPH Filed oct. .31, 196e '5 sheetsheet 1 Jlm 6, 1967 M.sAcHsENHAus ETAL 3,323,214

r V' ELLIPSOGRAPH Filed Oct. 51, 1966 5 Sheets-Sheet 2 Vrin/rales rrys.

June 6, 1967 M. sAcHsl-:NHAUS ETAL 3,323,214

ELLIPSOGRAPH I Filed Oct. 31, 1966 5 Sheets-Sheet /M/fA/mes dyrwy, r

United States Patent O 3,323,214 ELLIPSOGRAPH Marcel Sachseuhaus, 54Ave. de Stalingrad, Fontenaysous-Bois, and Pierre Cribier, 3 SquareServan, Paris, France Filed Oct. 31, 1966, Ser. No. 590,99() Claimspriority, application France, Nov. 5, 1965,

s claims. tcl. .as- 31) The present invention relates to an ellipsographof the kind comprising `a base adapted to be placed on a iiat workingsurface, two slides at right angles to each other carried at differentlevels on the base parallel to the said working surface, a rod slidingin each of the said slides and an operating unit comprising an operatingcrankhandle, the shaft of which is pivotally mounted on one of thesliding rods, a rst so-called operating rule keyed on the shaft of thesaid crank-handle, a guide adjustable in position along the saidoperating rule and pivotally mounted on the other sliding rod, a secondso-called drawing rule keyed on the said guide and `a tracing tooladjustably mounted in position along the said drawing rule.

The present invention has for its object improvements in an ellipsograph`of this kind, having the particular purpose of improving its accuracy,its operation and its utilization.

In accordance with one of these improvements, the operating unit ismovably mounted perpendicularly to the work surface against the actionof an elastic restoring means which urges the said unit in a directionsuch that, when at rest, the tracing tool is not in contact with thework surface.

It has already been proposed to suspend the tracing tool elastically insuch manner that this latter is continuously applied against the worksurface in order to absorb any possible surface irregularities of thislatter. In the present invention, it is the `operating unit which isWholly suspended elastically, in combination with a guidingperpendicular to the work surface, so that it is possible to obtain adelicate and accurate touch on the work surface by the tracing tool,which is removed from the said work surface in the position of rest; inaddition, this arrangement advantageously permits the drawing of brokenlines.

In accordance with another improvement of the invention, the drawingrule is keyed on the guide so as to be able to be adjusted angularly inposition with respect to this latter, that is to say, ultimately withrespect to the operating rule. This arrangement advantageously permitsthe drawing of identical and concentric ellipses, the axes of which havepivoted as a Whole about their common centre.

Other improvements and their advantages will also be brought out duringthe course of the description which follows below of one form ofembodiment shown by way of example and without limitation, referencebeing made to the accompanying drawings, in which:

FIG. l is a perspective view of an ellipsograph provided with theimprovements according to the invention;

FIG. 2 is a view in partial cross-section of this ellips-ograph, passingthrough the shaft of the operating crankarm;

FIG. 3 is a diagrammatic view from below of an alternative form ofconstruction of the base of the ellipsograph in accordance with theinvention;

FIG. 4 is a partial view in cross-section of this alternative, takenalong the line lV-IV of FIG. 3;

FIG. 5 is a partial view looking from below of an alternative form ofconstruction of a slide of the ellipsograph according to the invention;

FIG. 6 is a partial section of this alternative, taken along the lineVI-VI of FIG. 5;

FIG. 7 is a partial view similar to FIG. l, and concerns a furtherimprovement.

In accordance with the form of embodiment chosen and shown in FIGS. land 2, the ellipsograph according to the invention comprises a base 1having the form of a square, the arms of which each carry at their freeextremity a slide 11 mounted overhung. The slides 11 are located atdifferent levels with respect to the work surface 13. In its angle zone,the base 10 is weighted by a counter-weight 12. The arms of the base 10are extended in contact with the work surface 13 by lugs 14, eachpierced with a housing 15 permitting the arrangement of a retractablepin 16 for anchoring the base 10 on the work surface.

A rod or bar 17 slides in each of the slides 11; the upper rod 17carries at its extremity a socket with balls 18, which is describedlater, in which is rotatably and slidably mounted the shaft 19 of anoperating crankarm 20. Between the socket 18 and the arm 21 of thecrank-arm 20 is interposed a helicoidal spring 22 arranged coaxiallyround the shaft 19.

At the lower extremity of the shaft 19 of the crank-arm 20 is keyed aso`called operating rule 23, adapted to slide in a guide 24 which isslidably engaged on the rule 23 and can be locked in position along thisrule by tightening a screw 25. The guide 24 has a shaft. 26 rotatablyand slidably mounted in a socket with balls 27, carried at the extremityof the lower rod 17.

At the lower extremity of the shaft 26 of the guide 24 is arranged aso-called drawing rule 28 mounted with angular adjustment in positionwith respect to the shaft 26 by the action of a clamping screw 29. Onthe drawing rule 28 is slidably mounted a tracing tool 36; this tracingtool can be locked in position along the rule 28 by the action of aclamping screw 30.

The ball socket 18, shown in detail in FIG. 2, has the purpose ofensuring a strictly vertical guiding of the shaft 19 which passesthrough it. To this end, it comprises two rings of balls 31 and 32. Therings 31 and 32 are each associated with an annular cage 33 and 34respectively, and their balls are arranged in contact -on the one handwith the socket 13 and on the other hand with the shaft 19 which passesthrough this latter. In. addition, according to the invention, ahelicoidal spring 235 arranged in the socket 18 and at the base of thislatter, prevents the locking of the balls of the lower ring 32 when thelatter reaches the end of its downward travel. The socket 27 with ballsis similar t-o the socket 18.

In the position of rest, as shown in FIG. 2, the spring 22 urges upwardsthe operating unit formed conjointly by the operating crank-arm 20, therule 23, the guide 257 the rule 28 and the tool 36. Thus, in theposition of rest, the tool 36 is not in contact with the work surface13. The utilization of the apparatus according to the invention iseffected by adjustment of the positions of the guide 25 on the rule 23and of the tool 36 on the rule 28, as a function of the desiredcharacteristics of the ellipse to be drawn.

The drawing rule 28 is normally arranged along the plane which containsthe operating rule 23 and the shaft 26; the axes of the ellipses drawnthen correspond to the orthogonal projections of the sliding rods 17 onthe work surface. By acting on the screw 29, the drawing rule 28 can bebrought to make an angle with the operating rule 23. The axes of theellipses drawn are then displaced angularly as a whole by an equal anglewith respect to the axes previously defined, by rotation about theircommon centre.

It will be noted that, according to the invention, the overhang of theslides 11 leaves advantageously free the work face, which permits thedrawing of ellipses of large size, and that the elastic suspension ofthe operating assembly in combination with a guiding action on thislatter perpendicular to the work surface, makes it possible to obtain adelicate and accurate touch of the tracing tool on the work surface.

In accordance with the alternative form shown diagrammatically in theunderside view of FIG. 3 and the cross-section shown in FIG. 4, the baseis provided with three cylindrical feet 40, the apparent contour ofwhich slightly projects beyond the apparent contour of the base. Thecentral foot 40, that is to say that which is located in the angle zoneof the base 10, is adjustably mounted in Iposition with respect to thebase 10, in the direction of the arrows 41, so as to permit the planes42A and 42B tangential to the feet 41 form a perfectly straightdihedron. The central foot is then locked finally in this position.

This arrangement makes it possible to avoid accurate machining of thefaces of the lug 14 which are intended to bear against a work square.

In accordance with the form of embodiment shown in FIGS. 5 and 6, eachof the slides associated with a sliding rod 17 is formed by threebearing rollers 45, 46 and 47. The rollers 45 and 46 are arranged on thesame side of the rod 17, and the roller 47 is arranged on the other sideof this same rod, in a central position with respect to the rollers 45and 46. Each of the rollers 45, 46 and 47 is provided with a machinedexternal rolling strip in s-uch manner as to have two conical bearingsurfaces forming between them an angle 120, and conjointly, the rod 17is provided laterally with two grooves 48, 49 in the form of a V.

Each roller is carried by a shaft 50 fixed by a bolt 51 to the base 10.

The bolt 51 associated with the roller 47 passes eccentrically throughthe corresponding shaft 50, and conjointly, this shaft 50 is providedexternally with two small holes 52 enabling it to be rotated.

This arrangement permits a dynamometric adjustment of the pressure ofthe roller 47 on the rod 17, by causing the shaft 50 to rotate withrespect to the bolt by which it is carried.

Thus, as shown in FIG. 7, the operating rule 23 is providedalternatively at its extremity with a stop-screw 123. When the guide 24which slides on the rule 23 comes into abutment against the screw 123,the shaft 26 carried by this guide is located in the exact extension ofthe shaft 19 of the operating crank-arm. In such a case, theellipsograph obviously draws circles.

What we claim is:

1. An ellipsograph of the kind comprising a base adapted to be placed ona flat working surface, two slides at right angles to each other, saidslides being mounted at different levels on said base parallel to saidworking surface, a rod sliding in each of said slides, and an operatingassembly including an operating crank-handle having a shaft pivotallyand slidably mounted on one of said sliding rods, a first operating rulekeyed on the shaft of said crank-handle, a guide adjustable in positionalong said operating rule and pivotally and slidably mounted by a shafton the other sliding rod, a second drawing rule keyed on said lattershaft, a tracing tool adjustably mounted in position along said drawingrule, at least said tracing tool being movably mounted perpendicularlyto the working surface, and elastic restoring means which urges at leastthe tracing tool in such a direction that, when at rest, the tracingtool is not in contact with said working surface.

2. An elli-psograph as claimed in claim 1, in which said elasticrestoring means comprises a helicoidal restoring spring arrangedcoaxially around said first-named shaft.

3. An ellipsograph as claimed in claim 1, in which said drawing rule iskeyed on said guide in such manner as to be capable of being adjustedangularly in position with respect to said guide, that is to say withrespect to said operating r-ule.

4. An ellipsograph as claimed in claim 1, in which said two slides aremounted overhung on said base.

5. An ellipsograph as claimed in claim 1, in which said base is loadedwith a counter-weight opposite to said slides.

6. An ellipsograph as claimed in claim 1, in which said base issupported on said working surface by cylindrical feet, the apparentcontour of said feet projecting beyond the apparent contour of saidbase, the central foot being adjustably mounted in position on said baseparallel to said working surface.

7. An ellipsograph as claimed in claim 1, in which each said slide isconstituted by three rollers, each rotatably mounted with bearings on ashaft carried Iby said base, two of said rollers being disposed on thesame side with respect to the associated sliding rod, while the otherroller is arranged on the iother side of said sliding rod, the shaft ofsaid latter roller being Xed to said base by a bolt which passeseccentrically through said shaft.

8. An ellipsograph as claimed in claim 1, in which said operating rulecomprises an abutment means mounted in such manner as to stop the guidewhich it carries level with the shaft of said operating crank-handle.

No references cited.

LEONARD FOREMAN, Primary Examiner.

1. AN ELLIPSOGRAPH OF THE KIND COMPRISING A BASE ADAPTED TO BE PLACED ONA FLAT WORKING SURFACE, TWO SLIDES AT RIGHT ANGLES TO EACH OTHER, SAIDSLIDES BEING MOUNTED AT DIFFERENT LEVELS ON SAID BASE PARALLEL TO SAIDWORKING SURFACE, A ROD SLIDING IN EACH OF SAID SLIDES, AND AN OPERATINGASSEMBLY INCLUDING AN OPERATING CRANK-HANDLE HAVING A SHAFT PIVOTALLYAND SLIDABLY MOUNTED ON ONE OF SAID SLIDING RODS, A FIRST OPERATING RULEKEYED ON THE SHAFT OF SAID CRANK-HANDLE, A GUIDE ADJUSTABLE IN POSITIONALONG SAID OPERATING RULE AND PIVOTALLY AND SLIDABLY MOUNTED BY A SHAFTON THE OTHER SLIDING ROD, A SECOND DRAWING RULE KEYED ON SAID LATTERSHAFT, A TRACING TOOL ADJUSTABLY MOUNTED IN POSITION ALONG SAID DRAWINGRULE, AT LEAST SAID TRACING TOOL BEING MOVABLY MOUNTED PERPENDICULARLYTO THE WORKING SURFACE, AND ELASTIC RESTORING MEANS WHICH URGES AT LEASTTHE TRACING TOOL IN SUCH A DIRECTION THAT, WHEN AT REST, THE TRACINGTOOL IS NOT IN CONTACT WITH SAID WORKING SURFACE.